Disk drives are information storage devices that use magnetic media to store data. Referring to FIG. 1A, a typical disk drive 2 comprises a set of circular and concentric disks 201. Each disk 201 has a surface on which a magnetic coating is provided for forming a plurality of concentric tracks. The disks 201 are mounted on a spindle motor 202 that selectively spins the disks 201. A plurality of vertically-aligned sliders 203 incorporating read/write head therein (only one head is shown) are controllably carried and positioned by a HSA 200. A voice coil motor (VCM, not shown) rotates the HSA 200 to cause the sliders 203 to move across the surfaces of the disks 201 from track to track for reading data from or writing data to the disks 201. Both the spindle motor 202 and the HSA 200 are mounted to and supported by a base cover 205 of the disk drive 2. When in operation, a lift force is generated by the aerodynamic interaction between the slider 203 and the spinning disk 201. The lift force is opposed by equal and opposite spring forces applied by the HSA 200 such that a predetermined flying height above the surface of the spinning disk 201 is maintained over a full radial stroke of the HSA 200. The HSA 200 also comprises a ramp structure 230 to park the sliders 203 when the disk drive is not in operation.
FIG. 1B shows a detailed structure of the HSA of FIG. 1A. As illustrated, the HSA 200 comprises a set of drive arms 204 at one end thereof, wherein each drive arm 204 has a head gimbal assembly (HGA) 220 incorporating the slider 203 mounted on distal end of the drive arm 204. The drive arm 204 also has a locating hole 222 formed thereon for locating a shipping comb (not shown) used in process of mounting a HSA to the disk drive. The HSA 200 also comprises a fantail spacer 219 incorporating a voice coil 207 at the other end thereof, and the drive arms 204 are connected to the fantail spacer 219 by a bearing device 212. One end of a flexible printed circuit (FPC) 206 is electrically connected to the HSA 200, and the other end of the FPC 206 is electrically connected to a printed circuit board (PCB) 208. This electrical connection enables an external control system to control the HSA 200.
As illustrated above, in structure of a HSA, for maintaining a proper spring force that balances an equal and opposite lift force generated by aerodynamic interaction between the slider and the spinning disk, the distal end of each HGA is slightly downwards bended in manufacturing process of the HSA to produce a predefined spring force. More concretely, the distance between adjacent sliders mounted to respective HGAs is smaller than thickness of the disk. As a result, when assembling a head stack assembly to a disk drive, a special mounting tool, i.e., a comb-shaped shipping comb is used to facilitate the mounting process. More specifically, in HSA mounting process, the shipping comb is inserted into space formed between adjacent HGAs to enlarge the distance between the adjacent sliders, such that the disk can be accommodated in the space without interference with the sliders, thus no damage to the sliders and/or disks being happened.
Furthermore, when the disk drive with a ramp design is not in operation, the HSA moves its sliders away from above the disk surfaces until the sliders come to park on the ramp. The ramp is structured to park the set of sliders thereon and functions similarly as the shipping comb to separate adjacent sliders away from each other. During the disk drive operations, the HSA moves the sliders away from the ramp and then moves the sliders towards the disk surfaces, thereby positioning the respective sliders to a position above the respective disk surfaces.
Therefore, it is necessary to rotate the HSA to and park it on the ramp in HSA assembling process, such that when the assembly process is completed and the disk drive is operated, the sliders can be moved away from the ramp and located above the spinning disk surfaces. Conventionally, in HSA assembling process, parking the sliders onto the ramp is realized by utilization of the shipping comb abovementioned and this will be described below in conjunction with FIGS. 1A-1B and FIG. 2.
Now referring to FIGS. 1A-1B and FIG. 2, a conventional shipping comb 100 is of an integral structure, which comprises a comb finger 170 to separate two adjacent sliders 203 of a HSA 200 and an unmovable comb pin 120. Before the HSA 200 is mounted to the disk drive 2, the shipping comb 100 is secured to the HSA 200 by inserting its comb pin 120 into the locating hole 222 of the HSA 200. Then the bearing device 212 of the HSA 200 is pivotally mounted to the base cover 205 of the disk drive 2, and the sliders 203 of the HSA 200 are rotated towards the ramp 230, so that the sliders 203 can be parked thereto. After parking of the sliders 203 onto the ramp 230, other components for example top voice coil magnet (such as the top voice coil magnet 550 shown in FIG. 12A) and latch device (such as the latch device 540 shown in FIG. 12A) used to limit the position of the HSA, may be assembled to the disk drive.
In assembly process of above components, because of shaking or jolting inside the disk drive and the HSA mounted to the base cover of the disk drive rotating around the bearing device, consequently, the sliders parked on the ramp may slide away therefrom and collide with other part of the disk drive, for example, the sliders may impact the inner side wall of the disk drive, or the adjacent sliders collide each other, thus causing damage to the sliders. Therefore, in assembly process of the components such as the top voice coil magnet and the latch device, the HSA should be maintained stationary all the time by suitable manner until the components are mounted into the disk drive completely, as the top voice coil magnet and the latch device mounted into the disk drive are able to control position of the HSA and respective sliders with respect to the ramp.
However, since the conventional shipping comb described above has a comb pin that is position-fixed relative to the rest of the shipping comb, namely, the comb pin can be inserted only into the locating hole of the HSA, not both the HSA and the base cover of the disk drive, as a result, the shipping comb is unable to provide a function of holding the sliders of the HSA on the ramp during assembly process of other components. Therefore, various methods/devices are used in above assembly process to temporarily hold the HSA on the ramp.
One method commonly used is by forming a plurality of concave detents on the ramp. When parked on the ramp, the sliders are actually parked at these concave detents and these detents hold the sliders therein. However, due to dimension limitation of the ramp, the detents can not be formed sufficiently large, a slightly larger vibration will cause the sliders moving away from the detents of the ramp and making the HSA rotating freely around its bearing device, thus easily leading to slider damage or interference of the HSA with other components disposed in the disk drive.
Another method is using an additional locking mechanism to hole the HSA on its position. For example, a locating pilot may be inserted into both a locating hole and a respective hole formed on the base cover of the disk drive to temporarily secure the HSA on the base cover during process of assembling other components to the disk drive. However, this additionally provided locking device is time-consuming and difficult to be taken out after completing the whole assembly process. Moreover, this locking device is also difficult to be incorporated in an automatic assembly process of the HSA. Furthermore, providing this additional locking device increases manufacture cost.
Thus, it is desired to provide an apparatus and a method for easily assembling the HSA on the disk drive and simplifying its assembly process.